Interesting Briony. Have been having a good read of Prof. Studd's website and it's like he's describing me personally re: medical history of PMS, PND and thence suffering with peri menopausal depression/anxiety. He even says that a certain category of women who experience peri depression/anxiety won't experience any hot flushes or vaginal atrophy. So me, me, me!
I also read in a study of his how his team could actually induce PND in women by giving them very high doses of oestrogen and progesterone then suddenly stopping the dose. But even more interesting it was only in the women with a history of PMS who experienced the PND symptoms after the very high dose was suddenly withdrawn.
Further proof that some women cannot tolerate hormone fluctuations.
In the same study he mentioned that whilst continuous BCP will stop ovulation, the daily exposure to the synthetic progesterone can end up causing intense PMS symptoms in progesterone intolerant women and should be discontinued immediately if this is the case.